Adult Flea

The mouthparts look especially painful in this close-up view of the business end of an adult flea. Hoffman-style oblique illumination was used to increase contrast in the lower digital image of the unstained specimen.

Adult Flea at 200x Magnification(Brightfield)

Adult Flea at 200x Magnification(Oblique Illumination)

Fleas thrive in a warm and humid environment and, while wingless, they can jump as high as two feet. Approximately one percent of an entire flea population exists in the adult stage, making it critical to treat the entire environment when dealing with an infestation. Adult fleas are triggered to jump by a passing shadow and they can live for several months without food. Once attached to a host (dog, cat, human, etc.) they become permanent residents, although they only survive for three to four days after a blood meal. A female adult flea can lay only approximately 20 eggs per setting, but she is capable of producing up to 500 eggs in a lifetime.

Transmitted oblique illumination was obtained with a Hoffman-style substage condenser fitted with an offset aperture slit, which provides illumination from an oblique angle with respect to the optical axis of the QX3 microscope. Digital images were recorded with the QX3 interactive software operating from the Live View menu. In the case of birefringent specimens, a polarizer was added beneath the Hoffman condenser and an analyzer was placed in front of the QX3 lens cover. In some instances, a full-wave retardation plate was inserted between the specimen and the analyzer before capturing images.